Antilock control device

Abstract

An antilock control device includes a brake operation detecting unit, a wheel speed detecting unit, a control unit which detects a request for antilock control on the basis of a brake operation signal from the brake operation detecting unit and wheel speed signals from the wheel speed detecting unit and outputs a brake pressure control signal, and a brake pressure control circuit operative in response to said brake pressure control signal. The control unit has a judging function for detecting a request for starting antilock control while the vehicle speed is between a relatively low first predetermined speed and a higher second predetermined speed and the brake operation signal is OFF and a function of deciding whether to permit or prohibit the execution of antilock control. More specifically, if no request for starting antilock is detected, permission to execute antilock control is given while the vehicle speed is higher than the first predetermined value. If a request for starting antilock control is detected, the execution of antilock control is prohibited while the vehicle speed is between the first and second predetermined values. In another arrangement, even if such a request is detected, permission to execute antilock control is given while the vehicle speed is between the first and second predetermined speeds, provided the brake operation signal is ON.

What is claimed is: 
     
       1. An antilock control device comprising a brake operation detecting means, a wheel speed detecting means, a control means for detecting a request for antilock control on the basis of a brake operation signal from said brake operation detecting means and wheel speed signals from said wheel speed detecting means and for providing a brake pressure control signal, and a brake pressure control circuit operative in response to said brake pressure control signal, a judging means for judging whether or not a request for starting antilock control has been detected by said control means while the vehicle speed is within a range between a relatively low first predetermined value and a relatively high second predetermined value and said brake operation signal is OFF, and a permission/prohibition means for enabling said control means to issue said brake pressure control signal to said brake pressure control circuit while the vehicle speed is higher than said first predetermined value if said judging means judges that said control means has detected no request for starting antilock control, and for prohibiting said control means from issuing said brake pressure control signal to said brake pressure control circuit while the vehicle speed is between said first and second predetermined speeds if said judging means judges that a request for starting antilock control has been detected by said control means. 
     
     
       2. An antilock control device comprising a brake operation detecting means, a wheel speed detecting means, a control means for detecting a request for antilock control on the basis of a brake operation signal from said brake operation detecting means and wheel speed signals from said wheel speed detecting means and for providing a brake pressure control signal, and a brake pressure control circuit operative in response to said brake pressure control signal, a judging means for judging whether or not a request for starting antilock control has been detected by said control means while the vehicle speed is within a range between a relatively low first predetermined value and a relatively high second predetermined value and said brake operation signal is OFF, and a permission/prohibition means for enabling said control means to issue said brake pressure control signal to said brake pressure control circuit while the vehicle speed is higher than said first predetermined speed if said judging means judges that said control means has detected no request for starting antilock control, and if said judging means judges that a request for starting antilock control has been detected by said control means, to enable said control means to issue said brake pressure control signal to said brake pressure control circuit while the vehicle speed is higher than said second predetermined speed, or while the vehicle speed is within the range between said first predetermined speed and second predetermined speed providing that the brake operation signal is ON. 
     
     
       3. An antilock control device as claimed in claim 1, wherein said permission/prohibition means is so adapted that if no request for starting antilock control is detected by said judging means, permission to execute antilock control is given while the vehicle speed is higher than said first predetermined speed, and if a request for starting antilock control is detected by said judging means, said permission is given while the vehicle speed is higher than said second predetermined value, and permission only to continue antilock control is given while the vehicle speed is between said first and second predetermined speeds only if the brake operation signal is ON. 
     
     
       4. An antilock control device as claimed in claim 1, wherein said permission/prohibition means is so adapted that if no request for starting antilock control is detected by said judging means, permission to execute antilock control on said wheel to be controlled is given while the vehicle speed is higher than said first predetermined speed, and if a request for starting antilock control is detected by said judging means, said permission is given while the vehicle speed is higher than said second predetermined value, and permission only to start antilock control is given while the vehicle speed is between said first and second predetermined speeds only if the brake operation signal is ON. 
     
     
       5. An antilock control device as claimed in any of claims 1 or 2 or 3 or 4, wherein said permission/prohibition means is so adapted that if no request for starting antilock control is detected by said judging means, permission to execute antilock control on said wheel to be controlled is given while the vehicle speed is higher than said first predetermined speed, and if a request for starting antilock control is detected by said judging means, said permission is given while the vehicle speed is higher than said second predetermined value only if the brake operation signal is ON, and the execution of antilock control is prohibited while the vehicle speed is higher than said second predetermined value if the brake operation signal is OFF. 
     
     
       6. An antilock control device as claimed in claim 5, wherein said permission/prohibition means lifts the prohibition against antilock control on said wheel to be controlled while the vehicle speed is higher than said second predetermined speed and the brake operation signal is ON, if no request for the execution of antilock control is detected by the judging means for the wheels other than said wheel to be controlled. 
     
     
       7. An antilock control device as claimed in any of claims 1 or 2 or 3 or 4, wherein if no new request for the execution of antilock control is made for said wheel to be controlled by said judging means while a request for the execution of antilock control is being detected by said judging means, said permission/prohibition means is adapted to lift any previous prohibition against the execution of antilock control, thereby permitting the execution of antilock control as far as the vehicle speed is higher than the speed when the prohibition is lifted. 
     
     
       8. An antilock control device as claimed in claim 5, wherein if no request for the execution of antilock control is made for said wheel to be controlled by said judging means while a request for the execution of antilock control is being detected by said judging means, said permission/prohibition means is adapted to lift any previous prohibition against the execution of antilock control, thereby permitting the execution of antilock control as far as the vehicle speed is higher than the speed when the prohibition is lifted. 
     
     
       9. An antilock control device as claimed in claim 6, wherein if no new request for the execution of antilock control is made for said wheel to be controlled by said judging means while a request for the execution of antilock control is being detected by said judging means, said permission/prohibition means is adapted to lift any previous prohibition against the execution of anitlock control, thereby permitting the execution of antilock control as far as the vehicle speed is higher than the speed when the prohibition is lifted.